Energy Relationships in

At absolute zero the entropy of the system is zero (Refs la, p 265 7, pp 359-61 9, pp 67-8 10, pp 25-L 46-L) [See also Critical Energy of Impact in Detonation (and Explosion) and Detonation (and Explosion) Energy Relationships in] 

Theory of Detonation of Explosives , Lecture delivered at PicArsn on Dec 13, 1955 5) W. Fickett R.D. Cowan, p 265 in 2nd-ONRSympDeton (1955) JChemPhys 24, 

7) Clark Hawley(1957), 358-59 (Energy) 359-61 (Entropy) 8) Dunkle s Syllabus (1957-1958), 3-4 (Energy relationships)  

Explosivstoffe 1958, 25-L 46-L (Enthalpie) 45-L (Gesetz der Erhaltung der Energie) 46-L (Enthalpie und Energie) 52-R (Specifische Energie) 10a) A.N. 

Detonation (and Explosion), Energy Relationships in. Under the title Energy Relationships , C.G. Dunkle treats in the lecture, delivered at Picatinny Arsenal, Dover, NJ on Dec 13, 1955, pp 10-14, the following subjects a) Heat and energy of reaction of expls b) Heats of detonation and explosion c) Alternate deton rates d) Force, power or impetus of expls e) Brisance and f) Detonation pressure 

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The applicability of the two-parameter equation and the constants devised by Brown to electrophilic aromatic substitutions was tested by plotting values of the partial rate factors for a reaction against the appropriate substituent constants. It was maintained that such comparisons yielded satisfactory linear correlations for the results of many electrophilic substitutions, the slopes of the correlations giving the values of the reaction constants. If the existence of linear free energy relationships in electrophilic aromatic substitutions were not in dispute, the above procedure would suffice, and the precision of the correlation would measure the usefulness of the p+cr+ equation. However, a point at issue was whether the effect of a substituent could be represented by a constant, or whether its nature depended on the specific reaction. To investigate the effect of a particular substituent in different reactions, the values for the various reactions of the logarithms of the partial rate factors for the substituent were plotted against the p+ values of the reactions. This procedure should show more readily whether the effect of a substituent depends on the reaction, in which case deviations from a hnear relationship would occur. It was concluded that any variation in substituent effects was random, and not a function of electron demand by the electrophile. ... 

The development of linear ffee-energy relationships in aliphatic molecules is complicated because steric and conformational factors come into pl along with... 

It is perhaps interesting, in view of the very considerable success of Hammett plots, to say a word finally about the thermodynamic implications of linear free energy relationships in general. We have already mentioned (p. 359) the relationship between free energy change, AG, and log k or log K and each AG term is, of course, made up of an enthalpy, AH, and an entropy, AS, component ... 

Having said all that, it is equally important to remember that the number and variety of useful correlations to which Hammett plots have given rise is quite astonishing, particularly when we consider the simplicity and convenience of the approach. Indeed, linear free energy relationships in general constitute a testament to the theoretical utility of concepts that are purely empirical in their genesis ... 

The Rehm-Weller formulation of the free energy relationship in eq 17 can be rewritten as... 

Aqvist, J. and Warshel, A. Free energy relationship in metalloenzyme-catalyzed reactions. Calculations of the effects of metal ion substitutions in staphylococcal nuclease, J.Am.Chem.Soc., 112 (1990), 2860-2868... 

Conformational changes frequently involve free energy barriers small enough to allow structures spread across the whole reaction coordinate to be observed in a series of crystal structures (see Section 2). Rate constants are also readily obtained by suitable NMR experiments, so this is an attractive area for the examination of possible relationships between crystal structure correlations and free energy relationships. In fact not a great deal of work has been done, though more can confidently be expected. 

Vitha, M. and Carr, R.W., The chemical interpretation and practice of linear solvation energy relationships in chromatography, J. Chromatogr. A, 1126, 143, 2006. 

The pyridinium chlorochromate (PCC) oxidations of pentaamine cobalt(III)-bound and unbound mandelic and lactic acids have been studied and found to proceed at similar rates.Free-energy relationships in the oxidation of aromatic anils by PCC have been studied. Solvent effects in the oxidation of methionine by PCC and pyridinium bromochromate (PBC) have been investigated the reaction leads to the formation of the corresponding sulfoxide and mechanisms have been proposed. The major product of the acid-catalysed oxidation of a range of diols by PBC is the hydroxyaldehyde. The reaction is first order with respect to the diol and exhibits a substantial primary kinetic isotope effect. Proposed acid-dependent and acid-independent mechanisms involve the rapid formation of a chromate ester in a pre-equilibrium step, followed by rate-determining hydride ion transfer via a cyclic intermediate. PBC oxidation of thio acids has been studied. ... 

S Y Yang, MG Khaledi. Linear solvation energy relationships in micellar liquid chromatography and micellar electrokinetic capillary chromatography. J Chromatogr 692 301-310, 1995. 

Substituent effects on redox potentials can be rationalized by free energy relationships in many cases Although 1 can be related to aromatic compounds, a linear correlation with Hammett s a-constants fails. As can be seen from the substituents -N(CH3)2 Ik) and -OCH3 11) the electron attracting effect is the dominating one and not the resonance effect. Therefore Taft s a "-constants describe the substituent effects more correctly. According to (1)... 

C.G. Dunkle, "Energy Relationship in the RDX-TNT System", APL (Applied Physics Laboratory), Johns Hopkins Univ, Report CGD/M-10, Silver Spring, Md, July 22, 1964, p5 5) C.G. Dunkle, private communication, December 1967 and August 1968... 

This gives absolute temp Ti =3259+273 =3532°K Dunkle s Remark The above reaction for TNT is not far from what was figured by him in the APL Report, "Energy Relationships in the RDX-TNT Systems , CGD/M-10, July 22, 1964, p5 ... 

Ground and transition state Gibbs energy relationships in cationic intermediate resulted in the formulation of the nonclassical 7-norbornenyl (bishomocyclo-propenyl) cation (6).2... 

Free Energy Relationships, in Advances in Linear Free Energy Relationships (Chapman,... 

For a discussion of linear free-energy relationships in this reaction, see Bartoli Todesco Acc. Chem. Res. 1977, 10. 125-132. For a list of cr values, see Table 9.4. 

Energy Relationships in Detonation (and Explosion). See Vol 4 of Encycl, p D266... 

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